Various types of surgical staplers are known for repair of tears or separations in tissue. The use of various types of staplers has been used in gastric, colon, rectal, and/or esophageal surgery, for example, in gastric reconstructions performed end-to-end, end-to-side, or side-to-side.
The hand-sewn anastomosis has largely been replaced by the EEA (end to end anastomosis) stapling especially in colorectal and gastric bypass operations. For example, stapling the proximal colon to the lower rectum is easier to perform, and results in a similar anastomotic leak rate when compared to hand-sewn anastomosis.
The circular stapling device consists of an actuating head portion attached to an elongated tubular body with a handle on the opposed end of the body from the head. The anvil functions essentially as an end plate to turn in and close the ends of the staples. In one example of such a device, an instrument such as that disclosed in U.S. Pat. No. 5,119,983 is used to create an anastomosis. In this device, an anvil assembly is positioned on the end of a rod which is retracted within a tubular housing of the instrument. This instrument is introduced into the lumen of a stomach without the anvil in place, and then the tip of the center rod is passed through an opening which has been made at the anastomotic site and the anvil is then be secured on the end of the center rod. Alternately, the anvil is inserted into the intestine for securement to the rod and the end of the duodenum is then sutured off about the rod. Next, the rod is retracted towards the instrument to clamp the tissue between the anvil and the stapler body and then staples from the instrument are forced through the tissue and against the anvil so as to join the two sections of intestine to be joined such as the colon to the rectum or the stomach to the intestine positioned there between. With such a system, a relatively large incision need be made with attendant trauma to tissue and associated complications. The larger the hole, the less tissue available for staples to set. If the hole is too large, then some of the staples within the circular anastomosis are at risk to misfire and not land within tissue at all, thus causing leakage.
Even though current methods use detachable anvils; the insertion of the detachable anvil into the patient's body is still typically performed through a relatively large incision during open surgery and laparoscopic surgery. The smaller the opening in the recipient tissue made for anvil insertion, the more tissue available for the rows of staples in the circular anastomosis.
The tissue stapled together leaves a smaller opening than the original lumen into which the anvil and stapler were inserted. In order to insert the anvil through the smallest possible defect, it is desirable to provide an anvil which can be collapsed to introduce the anvil into the body through a relatively small incision and for removal of the anvil after stapling through the smaller opening between the staples.
What is needed is an applicator instrument with either a stationary or removable anvil that collapses to a small enough diameter enabling insertion and removal through small orifices to maximize tissue available for the staples to approximate the tissue.